The invention is a test probe for executing high-frequency measurements, in particular, for the measurement of electrical parameters during the testing of electronic circuits.
U.S. Pat. No. 4,871,964 Boll et al. “Integrated Circuit Probing Apparatus” proposes a test probe in which the inner conductor of a coaxial cable is first used to form the test probe that transmits the test signal to enable the inner conductor itself to be used directly to test an integrated circuit. The high-frequency ground potential, which is conducted by the outer conductor of the coaxial cable, is applied to the integrated circuit by means of two secondary contact tips that are finished as curved strips and soldered to the outer conductor.
In contrast to this, U.S. Pat. No. 5,506,515 Godshalk et al. “High-Frequency Probe Tip Assembly” proposes removing approximately half of the material at the freely suspended end of the coaxial cable so as to produce a flat plane, whose central area is formed by the inner conductor and whose outer areas are formed by the outer conductor of the coaxial cable. These areas are electrically insulated from one another by the dielectric fitted between the inner and outer conductors. Three coplanar contact points are soldered to this console and are used to transmit the test signal and the high-frequency ground potential to the integrated circuit to be tested.
The fundamental idea of attaching a test probe to this type of console is also adopted in U.S. Pat. No. 6,815,963 Gleason et al. “Probe for Testing a Device under Test”. However, this solution involves integrating all three measuring points into a common circuit card and fitting an elongate conductor to the top side of the circuit card. This conductor transmits the test signal from the inner conductor to the free end of the circuit board and transmits the high-frequency ground potential via at least one conductive element on the lower surface of the circuit card to its freely-suspended end. Contact elements are formed along the lower surface of the circuit card and are electrically connected to the elongate conductor and to the conductive element(s) for the purpose of transmitting the test signal and the high-frequency ground potential to the integrated circuit board to be tested. The elongate conductor on the top side is connected to a contact element on the lower surface of the circuit card by means of a conductive path running through the circuit card.